Below are most of the sites I visited. Forgive me, I have yet to learn how to put links on here (or anywhere else for that matter). I will give you the names of the blogs I visited though. I think all of them have a tutorial on how to make the colored glass, but each one is a little bit different.
gingerbreadsnowflakes.com
creativelittledaisy.typepad.com
sippycupmom.com
SaltTree.blogspot.com
As you can see there are various shades here. I'll explain that a bit....
This was my first attempt. Come to think of it, I did this one before I looked at any tutorials. I used the mod podge and food coloring mix together and put it on the outside of the bottle with a paint brush. It looks good from a distance, but not close up.
This was my attempt at putting the mixture inside of the bottle. It takes patience to swirl the color all around the bottle evenly & then to get all the excess color out. It also takes quite a while in the oven at a low temp to get it to dry. I was not patient on steps 2 and 3 that I just mentioned and as a result we got some gloppiness going on here. I ended up having to spend time soaking the bottle in hot water and getting it all out after it had dried. I ended up using a wire hanger to do that job! My daughter was grossed out by the glop but I was a bit fascinated.
My next attempts at coloring the inside and drying it in the oven. I still ended up with excess on the bottom of the jar but I can live with that.
And I just had to give one more method a try. This was painted on the outside with a foam brush. This is by far the fasted way to go, but as you can see you don't get much color.
And here they all are on my mantel. (Please don't judge my mantel....I don't have very strong decorator genes, but I'm working on improving what I do have.)
So, there you have it. My first attempts at colored glass. I'm pretty sure I will do it again in the future! I've already had my eye on several clear glass objects in my house...such as a vase on top of my bookcase and a votive candle holder in my cupboard.